Gas turbines in which a hot working medium flows past wings on moving blades in a ring-shaped hot gas channel are generally known. These blades are arranged as a ring on the outer perimeter of a turbine disc which sits on the rotor of the gas turbine. For fixing to the turbine disc, each blade has a fir-tree-shaped foot that slots into a corresponding groove running transverse to the outer perimeter of the turbine disc. Arranged between the wings of the blades and the blade feet connected to the turbine disc are platforms running transverse to the blades that delimit the hot gas channel on its radial internal side. To withstand thermal stresses, the platform is exposed to cooling fluid, as is the wing of a blade.